Final answer:
Glutaraldehyde is typically used to sterilize instruments by immersion for at least 10 hours, acting more quickly than formaldehyde due to its two reactive aldehyde groups. Ethylene oxide is used for gaseous sterilization, especially for heat-sensitive items in medical settings. Formaldehyde and phenol have historical significance as benchmarks for comparing disinfectant effectiveness.
Step-by-step explanation:
A chemical solution commonly used to sterilize instruments by immersing them for at least 10 hours is glutaraldehyde. Glutaraldehyde, marketed under the brand name Cidex, is used as a 2% solution for sterilization and is effective in disinfecting a variety of surfaces and surgical and medical equipment. As an alkylating agent, glutaraldehyde is structurally similar to formaldehyde but with two reactive aldehyde groups, making it act more quickly and efficiently.
Ethylene oxide is also used for sterilization, particularly as a gaseous sterilant for items that must remain in plastic packaging, like catheters and disposable lab items. Ethylene oxide is an effective cold sterilization method for heat-sensitive items but requires handling with care due to its carcinogenic and explosive properties.
Formaldehyde, another alkylating agent, acts by denaturing proteins and is used in a 37% solution called formalin for various purposes, including tissue preservation. The historical comparison of disinfectant effectiveness has been to phenol, which set the standard for measuring the efficacy of other disinfectants.